﻿/*==========================================================================
	TASK 5:                                                        {Loop's}
	Write a program that calculates N!*K! /(K-N)! for given N and K (1<N<K).   
==========================================================================*/

using System;
using System.Numerics;

class Program
{
    static void Main()
    {
        Console.Write("Enter N=");
        double n = double.Parse(Console.ReadLine());

        Console.Write("Enter K=");
        double k = double.Parse(Console.ReadLine());

        double product=1;

        for (int i = 1; i <= n; i++)
        {
            product *= k * i;
            k--;
        }

        Console.WriteLine(product);

    }
}